/Engine/Source/Runtime/Experimental/ChaosCore/Public/Chaos/ImplicitQRSVD.h
Compute WilkinsonShift of the block a1 b1 b1 a2 based on the WilkinsonShift formula mu = c + d - sign (d) \ sqrt (d*d + b*b), where d = (a-c)/2.
namespace Chaos { template<class T> T Chaos::WilkinsonShift ( const T a1, const T b1, const T a2 ) }